The invention relates to a method for producing hot strips from a deformable lightweight steel which is especially suitable for cold deep drawing and includes as main elements Fe, Mn, Si and Al and which has a high tensile strength and TRIP and/or TWIP properties.
The method, set forth in the preamble, for producing hot strips from a deformable lightweight steel which is especially suitable for cold deep drawing is known (steel research 74 (2003), No. 11/12, pp 724-731).
The production of such steels of high manganese content has been marred by problems to ensure a fine-grained and isometric microstructure.
DE 197 58 108 C1 discloses a production method and production installation for continuous production of hot-rolled thin flat products. Melt from steel that has not been designated in greater detail is cast in a horizontal continuous strip installation close to its final dimension in a range between 5-18 mm and cooled in a controlled manner under a protective gas atmosphere before reaching the single-stand roughing train.
The pre-rolled hot strip is selectively cooled, heated or maintained at a temperature in a controlled fashion in a device downstream of the roughing train, and the edges of the hot strip are re-heated.
The single-stand roughing train is followed by a multi-stand finishing train, a delivery roller table with a device for cooling the hot strip as well as upstream and downstream coiling machines for coiling up the hot strip.
Downstream of the roughing train, the rolling temperature upstream of the multi-stand finishing train can be selectively adjusted in the austenitic or ferritic range or tailored in the transition from austenite to ferrite by the device for controllable cooling, heating or maintaining the temperature of the hot strip.